def upgrade_ops(self):
"""An instance of :class:`.UpgradeOps`.
.. seealso::
:attr:`.MigrationScript.upgrade_ops_list`
"""
if len(self._upgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for UpgradeOps; please use the "
"upgrade_ops_list attribute.")
elif not self._upgrade_ops:
return None
else:
return self._upgrade_ops[0]
python类len()的实例源码
def downgrade_ops(self):
"""An instance of :class:`.DowngradeOps`.
.. seealso::
:attr:`.MigrationScript.downgrade_ops_list`
"""
if len(self._downgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for DowngradeOps; please use the "
"downgrade_ops_list attribute.")
elif not self._downgrade_ops:
return None
else:
return self._downgrade_ops[0]
def upgrade_ops(self):
"""An instance of :class:`.UpgradeOps`.
.. seealso::
:attr:`.MigrationScript.upgrade_ops_list`
"""
if len(self._upgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for UpgradeOps; please use the "
"upgrade_ops_list attribute.")
elif not self._upgrade_ops:
return None
else:
return self._upgrade_ops[0]
def downgrade_ops(self):
"""An instance of :class:`.DowngradeOps`.
.. seealso::
:attr:`.MigrationScript.downgrade_ops_list`
"""
if len(self._downgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for DowngradeOps; please use the "
"downgrade_ops_list attribute.")
elif not self._downgrade_ops:
return None
else:
return self._downgrade_ops[0]
def upgrade_ops(self):
"""An instance of :class:`.UpgradeOps`.
.. seealso::
:attr:`.MigrationScript.upgrade_ops_list`
"""
if len(self._upgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for UpgradeOps; please use the "
"upgrade_ops_list attribute.")
elif not self._upgrade_ops:
return None
else:
return self._upgrade_ops[0]
def downgrade_ops(self):
"""An instance of :class:`.DowngradeOps`.
.. seealso::
:attr:`.MigrationScript.downgrade_ops_list`
"""
if len(self._downgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for DowngradeOps; please use the "
"downgrade_ops_list attribute.")
elif not self._downgrade_ops:
return None
else:
return self._downgrade_ops[0]
def upgrade_ops(self):
"""An instance of :class:`.UpgradeOps`.
.. seealso::
:attr:`.MigrationScript.upgrade_ops_list`
"""
if len(self._upgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for UpgradeOps; please use the "
"upgrade_ops_list attribute.")
elif not self._upgrade_ops:
return None
else:
return self._upgrade_ops[0]
def downgrade_ops(self):
"""An instance of :class:`.DowngradeOps`.
.. seealso::
:attr:`.MigrationScript.downgrade_ops_list`
"""
if len(self._downgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for DowngradeOps; please use the "
"downgrade_ops_list attribute.")
elif not self._downgrade_ops:
return None
else:
return self._downgrade_ops[0]
def upgrade_ops(self):
"""An instance of :class:`.UpgradeOps`.
.. seealso::
:attr:`.MigrationScript.upgrade_ops_list`
"""
if len(self._upgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for UpgradeOps; please use the "
"upgrade_ops_list attribute.")
elif not self._upgrade_ops:
return None
else:
return self._upgrade_ops[0]
def downgrade_ops(self):
"""An instance of :class:`.DowngradeOps`.
.. seealso::
:attr:`.MigrationScript.downgrade_ops_list`
"""
if len(self._downgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for DowngradeOps; please use the "
"downgrade_ops_list attribute.")
elif not self._downgrade_ops:
return None
else:
return self._downgrade_ops[0]
def upgrade_ops(self):
"""An instance of :class:`.UpgradeOps`.
.. seealso::
:attr:`.MigrationScript.upgrade_ops_list`
"""
if len(self._upgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for UpgradeOps; please use the "
"upgrade_ops_list attribute.")
elif not self._upgrade_ops:
return None
else:
return self._upgrade_ops[0]
def downgrade_ops(self):
"""An instance of :class:`.DowngradeOps`.
.. seealso::
:attr:`.MigrationScript.downgrade_ops_list`
"""
if len(self._downgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for DowngradeOps; please use the "
"downgrade_ops_list attribute.")
elif not self._downgrade_ops:
return None
else:
return self._downgrade_ops[0]
def upgrade_ops(self):
"""An instance of :class:`.UpgradeOps`.
.. seealso::
:attr:`.MigrationScript.upgrade_ops_list`
"""
if len(self._upgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for UpgradeOps; please use the "
"upgrade_ops_list attribute.")
elif not self._upgrade_ops:
return None
else:
return self._upgrade_ops[0]
def downgrade_ops(self):
"""An instance of :class:`.DowngradeOps`.
.. seealso::
:attr:`.MigrationScript.downgrade_ops_list`
"""
if len(self._downgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for DowngradeOps; please use the "
"downgrade_ops_list attribute.")
elif not self._downgrade_ops:
return None
else:
return self._downgrade_ops[0]
def upgrade_ops(self):
"""An instance of :class:`.UpgradeOps`.
.. seealso::
:attr:`.MigrationScript.upgrade_ops_list`
"""
if len(self._upgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for UpgradeOps; please use the "
"upgrade_ops_list attribute.")
elif not self._upgrade_ops:
return None
else:
return self._upgrade_ops[0]
def downgrade_ops(self):
"""An instance of :class:`.DowngradeOps`.
.. seealso::
:attr:`.MigrationScript.downgrade_ops_list`
"""
if len(self._downgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for DowngradeOps; please use the "
"downgrade_ops_list attribute.")
elif not self._downgrade_ops:
return None
else:
return self._downgrade_ops[0]
def upgrade_ops(self):
"""An instance of :class:`.UpgradeOps`.
.. seealso::
:attr:`.MigrationScript.upgrade_ops_list`
"""
if len(self._upgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for UpgradeOps; please use the "
"upgrade_ops_list attribute.")
elif not self._upgrade_ops:
return None
else:
return self._upgrade_ops[0]
def downgrade_ops(self):
"""An instance of :class:`.DowngradeOps`.
.. seealso::
:attr:`.MigrationScript.downgrade_ops_list`
"""
if len(self._downgrade_ops) > 1:
raise ValueError(
"This MigrationScript instance has a multiple-entry "
"list for DowngradeOps; please use the "
"downgrade_ops_list attribute.")
elif not self._downgrade_ops:
return None
else:
return self._downgrade_ops[0]
def create_check_constraint(
cls, operations,
constraint_name, table_name, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the source table.
:param condition: SQL expression that's the condition of the
constraint. Can be a string or SQLAlchemy expression language
structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> table_name
"""
op = cls(constraint_name, table_name, condition, schema=schema, **kw)
return operations.invoke(op)
def create_check_constraint(self, name, source, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
`NamingConventions <http://www.sqlalchemy.org/trac/wiki/UsageRecipes/NamingConventions>`_,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param source: String name of the source table.
:param condition: SQL expression that's the condition of the constraint.
Can be a string or SQLAlchemy expression language structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or NOT DEFERRABLE when
issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value> when issuing DDL
for this constraint.
:param schema: Optional schema name to operate within.
..versionadded:: 0.4.0
"""
self.impl.add_constraint(
self._check_constraint(name, source, condition, schema=schema, **kw)
)
def create_check_constraint(
cls, operations,
constraint_name, table_name, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the source table.
:param condition: SQL expression that's the condition of the
constraint. Can be a string or SQLAlchemy expression language
structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> table_name
"""
op = cls(constraint_name, table_name, condition, schema=schema, **kw)
return operations.invoke(op)
def create_check_constraint(
cls, operations,
constraint_name, table_name, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the source table.
:param condition: SQL expression that's the condition of the
constraint. Can be a string or SQLAlchemy expression language
structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> table_name
"""
op = cls(constraint_name, table_name, condition, schema=schema, **kw)
return operations.invoke(op)
def create_check_constraint(self, name, source, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
`NamingConventions <http://www.sqlalchemy.org/trac/wiki/UsageRecipes/NamingConventions>`_,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param source: String name of the source table.
:param condition: SQL expression that's the condition of the constraint.
Can be a string or SQLAlchemy expression language structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or NOT DEFERRABLE when
issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value> when issuing DDL
for this constraint.
:param schema: Optional schema name to operate within.
..versionadded:: 0.4.0
"""
self.impl.add_constraint(
self._check_constraint(name, source, condition, schema=schema, **kw)
)
def create_check_constraint(
cls, operations,
constraint_name, table_name, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the source table.
:param condition: SQL expression that's the condition of the
constraint. Can be a string or SQLAlchemy expression language
structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> table_name
"""
op = cls(constraint_name, table_name, condition, schema=schema, **kw)
return operations.invoke(op)
def create_check_constraint(self, name, source, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param source: String name of the source table.
:param condition: SQL expression that's the condition of the
constraint. Can be a string or SQLAlchemy expression language
structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
"""
self.impl.add_constraint(
self._check_constraint(
name, source, condition, schema=schema, **kw)
)
def create_check_constraint(
cls, operations,
constraint_name, table_name, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the source table.
:param condition: SQL expression that's the condition of the
constraint. Can be a string or SQLAlchemy expression language
structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> table_name
"""
op = cls(constraint_name, table_name, condition, schema=schema, **kw)
return operations.invoke(op)
def create_check_constraint(
cls, operations,
constraint_name, table_name, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the source table.
:param condition: SQL expression that's the condition of the
constraint. Can be a string or SQLAlchemy expression language
structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> table_name
"""
op = cls(constraint_name, table_name, condition, schema=schema, **kw)
return operations.invoke(op)
def create_check_constraint(
cls, operations,
constraint_name, table_name, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the source table.
:param condition: SQL expression that's the condition of the
constraint. Can be a string or SQLAlchemy expression language
structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> table_name
"""
op = cls(constraint_name, table_name, condition, schema=schema, **kw)
return operations.invoke(op)
def create_check_constraint(
cls, operations,
constraint_name, table_name, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the source table.
:param condition: SQL expression that's the condition of the
constraint. Can be a string or SQLAlchemy expression language
structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> table_name
"""
op = cls(constraint_name, table_name, condition, schema=schema, **kw)
return operations.invoke(op)
def create_check_constraint(
cls, operations,
constraint_name, table_name, condition,
schema=None, **kw):
"""Issue a "create check constraint" instruction using the
current migration context.
e.g.::
from alembic import op
from sqlalchemy.sql import column, func
op.create_check_constraint(
"ck_user_name_len",
"user",
func.len(column('name')) > 5
)
CHECK constraints are usually against a SQL expression, so ad-hoc
table metadata is usually needed. The function will convert the given
arguments into a :class:`sqlalchemy.schema.CheckConstraint` bound
to an anonymous table in order to emit the CREATE statement.
:param name: Name of the check constraint. The name is necessary
so that an ALTER statement can be emitted. For setups that
use an automated naming scheme such as that described at
:ref:`sqla:constraint_naming_conventions`,
``name`` here can be ``None``, as the event listener will
apply the name to the constraint object when it is associated
with the table.
:param table_name: String name of the source table.
:param condition: SQL expression that's the condition of the
constraint. Can be a string or SQLAlchemy expression language
structure.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within. To control
quoting of the schema outside of the default behavior, use
the SQLAlchemy construct
:class:`~sqlalchemy.sql.elements.quoted_name`.
.. versionadded:: 0.7.0 'schema' can now accept a
:class:`~sqlalchemy.sql.elements.quoted_name` construct.
.. versionchanged:: 0.8.0 The following positional argument names
have been changed:
* name -> constraint_name
* source -> table_name
"""
op = cls(constraint_name, table_name, condition, schema=schema, **kw)
return operations.invoke(op)
